Agoraphobia-a Greek word that literally means "fear of the marketplace." This anxiety disorder involves the fear of experiencing a panic attack in a place or situation from which escape may be difficult or embarrassing.

Anorexia nervosa (Also called anorexia.) -an eating disorder in which people intentionally starve themselves. It causes extreme weight loss, which the National Institute of Mental Health (NIMH), part of the National Institutes of Health (NIH), defines as at least 15 percent below the individual's normal body weight.

Antisocial personality disorder - persons with this disorder characteristically disregard the feelings, property, authority, and respect of others, for their own personal gain. This may include violent or aggressive acts involving or targeting other individuals, without a sense or remorse or guilt for any of their destructive actions.

Anxiety-an intense feeling of fear or discomfort, often accompanied by physical symptoms, such and a pounding heart, sweating, nausea, rapid breathing, dizziness, or numbness.

Attention-deficit/hyperactivity disorder (ADHD) -a behavior disorder, usually first diagnosed in childhood, that is characterized by inattention, impulsivity, and, in some cases, hyperactivity.

Avoidant personality disorder-persons with this disorder are hypersensitive to rejection and thus, avoid situations with any potential for conflict. This reaction is fear-driven, however, persons with avoidant personality disorder become disturbed by their own social isolation, withdrawal, and inability to form close, interpersonal relationships.

Binge eating disorder-a disorder that resembles bulimia nervosa and is characterized by episodes of uncontrolled eating (or bingeing). It differs from bulimia, however, because its sufferers do not purge their bodies of the excess food, via vomiting, laxative abuse, or diuretic abuse.

Bingeing-persons with bulimia nervosa engage in a destructive pattern of excessively overeating, called bingeing.

Bipolar disorder-a spectrum of mood swing disorders (see manic depression) which can specify the rhythmns of cycles an individual experiences.

Body dismorphic disorder-the excessive preoccupation with either a small or imagined defect in one's physical appearance.

Borderline personality disorder-persons with this disorder present instability in their perceptions of themselves, and have difficulty maintaining stable relationships. Moods may also be inconsistent, but never neutral - their sense of reality is always seen in "black and white." Persons with borderline personality disorder often feel as though they lacked a certain level of nurturing while growing up and, as a result, incessantly seek a higher level of caretaking from others as adults. This may be achieved through manipulation of others, leaving them often feeling empty, angry, and abandoned, which may lead to desperate and impulsive behavior.

Child and adolescent psychiatrist-licensed physicians (M.D. or D.O.) who specialize in the evaluation, diagnosis, and treatment of mental disorders in children and adolescents. Their medical and psychiatric training with children and adolescents prepares them to treat children and adolescents either individually, as part of and involving the family unit, and/or in a group setting. Child and adolescent psychiatrists can prescribe medications, if needed.

Circadian rhythmn sleep disorder -a disruption in the normal sleep-wake cycle over a period of time, as found in shift work, jet lag, or other delayed sleep.

Delerium -an altercation in consiousness, with a decrease in the ability to focus, hold ,or shift attention.

Delusions-a perception that is thought to be true by the person experiencing it, although the perception is wrong. There are many types of delusions (i.e., delusions of grandeur).

Dependent personality disorder-persons with this disorder rely heavily on others for validation and fulfillment of basic needs. Often unable to properly care for themselves, persons with dependent personality disorder lack self confidence and security, and are deficient in making decisions.

Dysthymia (Also known as dysthymic disorder.)-classified as a type of affective disorder or mood disorder that often resembles a less severe, yet more chronic form of major (clinical) depression. However, persons with dysthymia may also experience major depressive episodes at times.

hallucinations-a strong perception of an event or object when no such situation is present; may occur in any of the senses (i.e., visual, auditory, gustatory, olfactory, or tactile).

Histrionic personality disorder-persons with this disorder are overly conscious of their appearance, are constantly seeking attention, and often behave dramatically in situations that do not warrant this type of reaction. The emotional expressions of persons with histrionic personality disorder are often judged as superficial and exaggerated.

Learning disorders -seen in childhood; also identified in adulthood. Reading, writing, and mathematical calculations are challenging to understand and express. May interfere with social, work, and academic progression.

Major depression (Also known as clinical depression or unipolar depression.)-classified as a type of affective disorder or mood disorder that goes beyond the day's ordinary ups and downs, becoming a serious medical condition and important health concern in this country.

Narcissistic personality disorder-persons with this disorder present severely overly-inflated feelings of self-worth, grandiosity, and superiority over others. Persons with narcissistic personality disorder often exploit others who fail to admire them, and are overly sensitive to criticism, judgment, and defeat.

Neurotransmitters-chemicals in the brain that regulate other chemicals in the brain.

Obsessive-compulsive disorder (OCD)-an anxiety disorder in which a person has an unreasonable thought, fear, or worry that he or she tries to manage through a ritualized activity to reduce the anxiety. Frequently occurring disturbing thoughts or images are called obsessions, and the rituals performed to try to prevent or dispel them are called compulsions.

Obsessive-compulsive personality disorder-persons with this disorder are inflexible to change and bothered by a disrupted routine due to their obsession for order. Thus, they experience anxiety and have trouble completing tasks and making decisions. Persons with obsessive-compulsive personality disorder often become uncomfortable in situations that are beyond their control and have difficulty maintaining positive, healthy interpersonal relationships as a result.

Panic disorder-characterized by chronic, repeated, and unexpected panic attacks - bouts of overwhelming fear of being in danger when there is no specific cause for the fear. In-between panic attacks, persons with panic disorder worry excessively about when and where the next attack may occur.

Paraphilias-a cluster of psychosexual disorders which include sexual behaviors that include suffering and humiliation directed towards a nonconsenting partner.

Paranoid personality disorder-persons with this disorder are often cold, distant, and unable to form close, interpersonal relationships. Often overly, yet unjustifiably, suspicious of their surroundings, persons with paranoid personality disorder generally cannot see their role in conflict situations and often project their feelings of paranoia as anger onto others.

Phobia-an uncontrollable, irrational, and persistent fear of a specific object, situation, or activity.

Post-traumatic stress disorder (PTSD)-a debilitating condition that often follows a terrifying physical or emotional event causing the person who survived the event to have persistent, frightening thoughts and memories, or flashbacks, of the ordeal. Persons with PTSD often feel chronically, emotionally numb. Once referred to as "shell shock" or "battle fatigue."

Psychiatric nurse- may have a Master's degree in psychiatric mental health nursing. An advanced practice psychiatric nurse is educationally and clinically trained in psychopathology, individual, group, family therapy, and crisis intervention. They may also be licensed to prescribe psychotropic medications.

Psychiatrist-licensed physicians (M.D. or D.O.) who specialize in the evaluation, diagnosis, and treatment of mental disorders. Their medical and psychiatric training prepares them to treat adults and children either individually, as part of and involving the family unit, and/or in a group setting. Psychiatrists can prescribe medications, if needed.

Psychologist-a specialist in the study of the structure and function of the brain and related behaviors or mental processes. A psychologist may provide psychological evaluation, assessment, testing, and treatment, but may not prescribe medications.

Psychosis-a loss of contact with reality.

Purging-persons with bulimia nervosa engage in a destructive pattern of ridding their bodies of the excess calories (to control their weight) by vomiting, abusing laxatives or diuretics, taking enemas, and/or exercising obsessively - a process called purging.

Sexual dysfuctions-a cluster of disorers, including problems with pain, arounsal dysfunctions, and organ achievement not related to medication or a medical condition.

Schizoid personality disorder-persons with this disorder are often cold, distant, introverted, and have an intense fear of intimacy and closeness. Persons with schizoid personality disorder are often too absorbed in their own thinking and daydreaming that they exclude themselves from attachment with persons and reality.

Schizophrenia-one of the most complex of all mental health disorders; involves a severe, chronic, and disabling disturbance of the brain.

Schizotypal personality disorder-similar to schizoid personality disorder, persons with this disorder are often cold, distant, introverted, and have an intense fear of intimacy and closeness. Yet, with schizotypal personality disorder, persons also exhibit disordered thinking, perception, and ineffective communication skills. Many symptoms of schizotypal personality disorder resemble schizophrenia, but are less mild and intrusive.

Seasonal affective disorder (SAD)-a mood disorder characterized by depression related to a certain season of the year - especially winter.

Social phobia-an anxiety disorder in which a person has significant anxiety and discomfort related to a fear of being embarrassed, humiliated, or scorned by others in social or performance situations.

Specific phobia-a type of phobia characterized by extreme fear of an object or situation that is not harmful under general conditions.

Substance abuse disorder-includes alcohol and drug misuse and abuse. Problems extend into the social, family, and occupational functions of the affected person. Any drug, including alcohol, that is used in excess of legal limits or prescription directions is considered abusive. Intoxication and withdrawal are common problems in the abusing population.

Suicidal behavior-actions taken by one who is considering or preparing to cause their own death.

Suicidal ideation-thoughts of suicide or wanting to take one's life.

Suicide-the intentional taking of one's own life.

Suicide attempt-an act focused on taking one's life that is unsuccessful in causing death.